Health Highlights: April 23, 2014

Ebola Death Toll in West Africa at 147: WHO

U.S. Issues Rules to Reduce Coal Miners' Risk of Black Lung

Artificial Retina Restores Vision

Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

Ebola Death Toll in West Africa at 147: WHO

The Ebola outbreak in West Africa has killed 147 people so far, according to the World Health Organization.

More than 240 cases of the virus have been recorded in Guinea and Liberia. Most of the cases and 136 deaths have been in Guinea, while 11 people have died in Liberia, the agency said in a statement posted on its website, the Associated Press reported.

The outbreak in West Africa is unusual because Ebola typically occurs only in central or eastern Africa.

There is no vaccine or cure for Ebola, which has a high death rate and causes high fever and internal and external bleeding, the AP reported.

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U.S. Issues Rules to Reduce Coal Miners' Risk of Black Lung

New limits on the amount of coal dust allowed in mines have been introduced by the U.S. government in an attempt to lower the number of miners who develop black lung disease, an irreversible and potentially deadly disease caused by the accumulation of coal dust particles in the lungs.

Under the rule announced Wednesday, the overall coal dust standard will be reduced from 2.0 to 1.5 milligrams per cubic meter of air. For certain mine entries and miners with black lung disease, the standard goes from 1.0 to 0.5, the Associated Press reported.

The frequency of coal dust sampling will increase and coal mine operators will have to take immediate action when levels are too high. They'll also have to use new technology that shows real-time dust levels. The changes will be phased in over two years.

"Today we advance a very basic principle: you shouldn't have to sacrifice your life for your livelihood," Labor Secretary Thomas Perez said, the AP reported. "But that's been the fate of more than 76,000 miners who have died at least in part because of black lung since 1968."

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Artificial Retina Restores Vision

Four Americans have received an artificial retina since it was approved by the U.S. Food and Drug Administration last year, and a fifth is scheduled to receive the implant next month.

The device is meant to help people with retinitis pigmentosa, an inherited disease that causes progressive damage to light-sensitive cells in the eye's retina.

The "bionic eye" system includes an array of electrodes implanted on the surface of the retina. The person wears glasses that contain a tiny video camera and transmitter. Images from the camera are converted into electrical pulses that are sent to the electrodes and stimulate the retina's remaining healthy cells, the Associated Press reported.

Dozens of patients in Europe have undergone the artificial retina procedure in recent years. All four of the surgeries in the United States have been performed at the University of Michigan Kellogg Eye Center, but 11 other centers in the country are accepting patients for consultation.

To be considered for the artificial retina, patients must be 25 and older and have end-stage retinitis pigmentosa that has left them with little or no light perception in both eyes, the AP reported.

About 100,000 people in the U.S. have retinitis pigmentosa. Of those, about 10,000 could benefit from the artificial retina, according to Dr. Brian Mech, an executive with California-based Second Sight Medical Products Inc, which makes the device.

The artificial retina is a "game changer," according to Dr. Thiran Jayasundera, one of two surgeons involved in a 4.5-hour procedure to implant the device in 55-year-old Roger Pontz of Reed City, Mich.

He was diagnosed with retinitis pigmentosa as a teen and had been almost completely blind for years. The bionic eye has restored enough of his vision to enable him to see his wife, grandson and cat, and to be able to walk through the house with ease.